Accessory dwelling unit construction cost — Spokane Valley, WA
Last updated: September 24, 2026
What affects the price
Building an ADU involves variables that shift your total investment. The footprint size and complexity of the architectural design are primary factors. Are you planning a detached unit that requires new utility trenching, or is this a garage conversion that uses existing plumbing? Site accessibility, soil conditions, and your choice of finishes—like luxury flooring versus standard options—also play significant roles. Permitting fees vary widely depending on your local municipality and current zoning requirements. Exact pricing confirmed free on the call.
About this service
The amount you spend depends on the size of the unit, whether you are building from scratch or converting an existing structure, and the quality of your finish materials. Foundations, utility connections, and local labor rates also play a significant role. We provide exact pricing confirmed free on the call.
Frequently asked in Spokane Valley
What are accessory dwelling unit homes like?
How do I get an ADU estimate in Spokane Valley?
What is the best ADU for my property?
Are there affordable ADU options in Spokane Valley?
What's involved in ADU construction?
What ADU permits are needed in Spokane Valley?
What are prefabricated ADUs?
Also serving nearby: Spokane · Yakima · Bellevue · Renton · Kirkland
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Spokane Valley — population 108,235; about 2,869 residents per square mile across 37.7 sq mi.
Neighborhoods served in Spokane Valley: Millwood, Opportunity, Ponderosa, Harvard Heights, Glenrose — and every surrounding area.
Areas we serve
Browse by state, then city.